*4.2. Coating Solutions Preparation*

The chitosan solution was prepared according to the method described by [50]. Chitosan powder was mixed with distilled water containing glacial acetic acid (0.5% *v*/*v*) at 70 ◦C under stirring until fully dissolved to produce a 2% chitosan solution. Finally, the pH of the solution was adjusted to 5.6 with 1 N NaOH.

The sodium alginate solution was prepared according to the method described by [11], with some modifications. Sodium alginate powder was dissolved in 100 mL of distilled water to obtain a 2% concentration. Then, the solution was stirred in a 70 ◦C water bath for 2 h to dissolve completely. Finally, the sodium alginate solution was cooled at room temperature.

Calcium chloride was used as the cross linking agent to produce gel coatings via layerby-layer treatment. Calcium chloride was weighed and dissolved in 100 mL of distilled water to obtain a 2% solution. Then, the solution was shaken in the incubator to become dissolved entirely.
